@ink_slinger not sure it is far fetched enough, but the ones I struggle to not get paranoid about relate to food and diet.
Like, I think government food guides were created for, and designed to, address industry concerns ahead of public health. For example they historically over-emphasize the importance of consuming dairy, meats etc. to encourage demand for milk, corn etc. Also the heavy focus on the harm caused by fat and cholesterol but less so on refined sugars and starches.